Hand-operated drive-in devices having propellant charges are known from the prior art, in which the resulting combustion gases expand in a combustion chamber following ignition of a pyrotechnic charge. A piston is thereby accelerated as an energy transmission means and drives a fastening element into a workpiece.
A known pyrotechnic drive-in device is distributed by the Hilti Corporation, Schaan, Liechtensten under the name DX 36. In this device the drive-in energy of a piston can be reduced as needed through controlled setting of the starting position of the piston in a combustion chamber. For this purpose, a handwheel is provided on the device, the handwheel being displaced laterally to a center axis of the piston in a rear section of the device relative to the drive-in direction.
The device DX 36 also constitutes a type of drive-in devices not having automatic piston return. In the DX 36, the piston is brought into a starting position through a manual repeater motion following a drive-in action. For this purpose, a piston guide is, in a first stage of the repeater motion, shifted forward together with the piston in the drive-in direction until a defined stop arrests this movement. In a second stage of the repeater motion, the piston guide is shifted rearward in the opposite direction until the piston guide reaches a defined rear stop.
In the device DX 36 the piston is, through a first stage of the repeater motion, brought to a rear position in the piston guide, which corresponds to a starting position with maximum drive-in energy. In the course of the second stage of the repeater motion the piston element can be shifted as needed by means of an adjustable stop to a preset starting position relative to the piston guide.
The invention seeks to solve the problem of providing a drive-in device that allows a drive-in energy to be set in a simple manner for a given propellant charge.